Lateral Stability Research Based On Automobile SBW System

The improvement of the lateral stability for the vehicle during driving has great significance for reducing personal safety injuries caused by traffic accidents and improving the driving safety of vehicles under extreme conditions such as high-speed steering or continuous obstacle avoidance.The ever-increasing demand for safe and comfortable driving has prompted vehicle manufacturers and suppliers to actively seek development in the so-called"wire control technology"subsystem project.The automobile SBW system（Steer-By-Wire System）uses wire control technology to transmit signals to the ECU through wires,and control the executive motor to drive the steering wheels to complete the steering.At the same time,the steering wheel resistance when turning is also generated by the motor simulation.The first advantage of the steer-by-wire system is that the ECU can control the steering,simulate the road feel,and record the driver’s steering habits,so as to help the driver to manipulate the vehicle more easily;the second advantage is that it can filter out rough roads Disturbance torque caused by changes in temperature and parameters,and these factors are usually caused by tire pressure,tire temperature and load changes.Based on the automobile SBW system,this paper uses the two-way controller and layered coordinated control method to study the lateral stability of the vehicle,and uses the control algorithm to assist in improving the steering demand of the driver.First,analyze and model the dynamics of the SBW system and the vehicle,and then complete the construction task in the Simulink software environment.The stability of the vehicle system is judged according to the quasi-stability tolerance,and the vehicle model is compared with the established reference model.When the difference between the two exceeds a certain range,the vehicle starts to control the stability of the vehicle.In order to meet the regulation requirements,it is necessary to design the SBW control system,determine the overall structure of the hierarchical coordinated control,and design and verify the upper controller—fuzzy PID controller and the lower controller—two-way controller.Finally,in order to reduce the impact of the internal collision of the steering gear on the stability of the vehicle during steering,prevent the rigid collision between the elastic limit device at the steering gear rack and the steering gear,and at the same time control the limitation corner of the wheel,analyze the bifurcation diagram of the nonlinear system,find out the influence of the elastic limit device structural parameter₍（8） on the motion state of the vehicle system,and judge its stable state and interval through the Lyaponuv index diagram.